Starter switch



C. PENK STARTER SWITCH June 3, 1947.

Filed April 24, 1945 JMI/I 1 .1."

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INVENTOR (fine/9x55 fkw/r AT OR.NEY

Patented June 3, 1947 STARTER SWITCH Charles Penk, Newark, N. J., assignor to Sal-Mar Laboratories, Inc., Irvington, N. J., a corporation of New Jersey Application April 24, 1945, Serial No. 590,075

2 Claims.

The invention here disclosed relates to switches for starting fluorescent lamps and other gaseous discharge devices.

Special objects of the invention are to provide a starter of the thermal type which will be relatively simple and inexpensive, consist of but few parts and be of a rugged nature, not liable to get out of order.

Further important objects are to provide a thermal starter which in its action will afford the necessary and proper time for starting a lamp or other discharge device and which if the device should fail to start, will continue in action until a start is effected.

Other desirable objects and the novel features by which the purposes of the invention are attained are set forth or will appear in the course of the following specification.

The drawing accompanying and forming part of the specification illustrates certain present preferred embodiments of the invention but structure may be modified and changed as regards the present illustration, all within the true intent and broad scope of the invention as hereinafter defined and claimed.

Fig. 1 in the drawing is a front elevation of one of the starters;

Fig. 2 is a side view of the same;

Figs. 3 and 4 are diagrammatic views illustrating operation of the device;

Fig. 5 is a partly diagrammatic view illustrating a modified form of the invention.

In Figs. 1 and 2 the starter is shown as comprising a thermostatic element in the form of a bimetal strip supported at one end at 1 and made up of two longitudinally connected portions 8 and 9, the first or base portion 8 being curved and arranged to bend into closer coiled formation under heat and the other, end or free portion 9 being substantially straight and arranged, under heat, to bend outwardly, in the opposite direction.

These two oppositely acting sections of bimetal may be connected by Welding them together in end-to-end relation, as indicated at 10.

A high resistance heater or resistor II is disposed within the curve of the inwardly bending base section 8 and a low resistance heater I2 is shown in the form of a coil of heating wire about the outwardly bending end portion 9 of the compound bimetal.

The high resistance heater H is shown directly connected at l3, M, with the terminals l5, 16, by which the device is mounted and connected in the starting circuit, and the low resistance heating coil I2 for the free end of the compound th'ermostatic element is shown connected at one end at I! with one of the circuit terminals, i5, and at the opposite end at l8 with a stationary contact I9 disposed in the path of closing movement of a contact 2|! on the free end of the thermostatic member.

In the cold or out-of-service condition of the starter the free end of the thermostatic element is separated from the stationary contact I!) substantially as indicated in Fig. 2.

By reference to the wiring diagram, Fig. 3, it will be seen that the high resistance heater H, through terminals l5, I6, is directly connected in a starting circuit made up of wires 2|, 22, connected each with one end of one of electrodes 23, 24, of the lamp or other gaseous discharge device 25, which electrodes have their other ends connected by wiring 26, 21, in a supply circuit including starting reactance 28 and a suitable control switch 29.

When the switch 29 is closed the electrodes will be connected in series relation through wiring 2 l terminal l5, connection l3, high resistance heater II, connection l4, terminal 16 and wiring 22.

The heat than generated by this high resistance heater has the effect of bending the curved base portion more closely about the heater. At the same time, but possibly to a lesser extent, the other end portion 9 of the bimetal is bending outwardly in the opposite direction. The full line voltage to which the high resistance heater is subjected at the time has the effect of shifting the bimetal in a circuit closing direction faster than the end of the bimetal is bending away from the fixed contact [9. Consequently the combined result will be a closing of circuit between contacts 19 and 20, as in Fig. 3. Incidentally when this circuit is closed, the high resistance heater II is short circuited through the low resistance heater coil [2.

The immediate effect of this is to take away heat from the curved base portion of the thermostat so that it will start to curl and bend away from the resistor, in the circuit opening direction. At the same time the free end of the thermostat is being heated by low resistance coil I2 and this portion then is being bent outward in the circuit opening direction. The combined result then will thus be to interrupt the low resistance shunt circuit through coil l2, as in Fig. 4, to flash the lamp or other discharge device 25.

If the gaseous discharge device starts at this first attempt, the starter will remain approximately as in Fig. 4 with the end of the bimetal separated from contact 19, with the low resistance heater coil 12 out of circuit. This is the normal position while the lamp or other discharge device continues in operation. During such time of lamp operation the high resistance heater II will be in circuit but in parallel relation with the discharge between the electrodes so as to take practically no current, and at any rate not enough current to heat the bimetal sufficiently to close the low resistance starter circuit.

If the lamp should not start or if the lamp should fail after having been started, the full line voltage will again be impressed on the high resistance heater and the latter will then furnish sufiicient heat to cause the thermostat to close the circuit 19, 20, as above described, and the device will then go through another starting cycle. This closing and opening of the low resistance starting circuit may continue until starting of the lamp is accomplished.

The low resistance heater coil about the outwardly bending free end portion of the thermostat has the effect of speeding up the circuit breaking operation. If a longer preheating time is desired, and this may be the case in cold weather or in exposed or cold situations, the heating coil [2 may be omitted, as indicated in Fig. 5, and the relatively stationary contact H) be directly connected with the circuit terminal l5 by a direct wire or other connection 30.

The operation then will be as described except that separation of contact 20 from contact 19 may be slower, giving the electrodes 23, 24, more time to heat up for starting purposes.

The open circuit condition leaves the thermostatic element free of mechanical tension when the device is cold and not in use. The bending force resulting from the heating of the thermostatic element furnishes spring tension for holding the contacts engaged. Consequently the circuit closing engagement of the contacts will be firm and assure a good starting circuit connection.

The base portion of the bimetal may contact or substantially engage the high resistance heater which it partially surrounds or encloses. The low resistance heating coil may be suitably insulatedfrom that portion of the bimetal which it surrounds as by a layer or layers of asbestos paper, tape or other suitable insulating material 3|. The operating parts may be contained within asuitable enclosure, such as a metallic can lined with insulating material, or they may be sealed within an enclosure of g ass 1 t e like. in some instances under partial vacuum or in an atmosphere of inert gas.

The invention is suitable for both A. C. and D. C. circuits.

The welded or brazed connection it) between the dissimilar or oppositely acting sections of the bimetal has a tendency to slow up thermal conductivity and this, for some purposes, may be an advantage. In some instances thi interruption or variation in thermal conductivity may not be desired. In such event continuous or substantially uniform conductivity may be provided by making the bimetal continuous in extent from end to end and twisting it or reversing the faces of the two metals forming the bimetal at the intermediate point.

In some instances the two sections of bimetal may be mechanically held together but be electrically or thermally or both electrically and thermally insulated from each other.

What is claimed is:

1. A thermal starter for gaseous discharge devices comprising a thermostatic element having a curved base portion arranged to bend, under heat, in closer coiled relation and a free end portion extending straight from the end of said curved base portion and arranged to bend, under heat, in the opposite direction, a high resistance heater disposed within the curved base portion, a switch contact disposed in the path of movement of the free end portion of the thermostatic element and a low resistance shunt about said high resistance heater connected with said switch contact.

2. A thermal starter for gaseous discharge devices comprising a thermostatic element having a curved base portion arranged to bend, under heat, in closer coiled relation and a free end portion extendin straight from the end of said curved base portion and arranged to bend, under heat, in the opposite direction, a high resistance heater disposed within the curved base portion, a switch contact disposed in the path of movement of the free end portion of the thermostatic element and a low resistance shunt about said high resistance heater connected with said switch contact, said switch contact being disposed at the side of the free end portion which i in the closing direction of the curved portion of the thermostatic element, said shunt including a low resistance heater coil on said straight portion of the thermostatic element connected with said switch contact and arranged when engaged by the free end portion ofthe thermostatic element to short circuit the high resistance heater and whereby the cooling effect resulting from short circuiting of the high resistance heater will be combined with theheating effectof the low resistance heater to accomplish separation of the thermostatic element from said switchcontact.

CHARLES PENK.

REFERENCES CITED The followingreferences are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,367,645 Hodgkins et al. Jan. 16, 1945 2,303,153 Woodworth Nov. 24, 1942 2,343,172 Cook Feb. 29, 1944 2,259,111 Laidg Oct. 14, 1941 

